A kidney stone, also known as a renal calculus, is a solid concretion or crystal aggregation formed in the kidneys from dietary minerals in the urine. Urinary stones are typically classified by their location in the kidney (nephrolithiasis), ureter (ureterolithiasis), or bladder (cystolithiasis), or by their chemical composition. For example, kidney stones can be formed from calcium-containing substances, struvite, uric acid, or other compounds.
Nephrolithiasis is a worldwide health problem responsible for significant economic cost to society and serious effects on quality of life. Over the past few decades, it had been shown that stone disease incidence and prevalence steadily increased, attributed presumably to changes in diet and lifestyle. Uric acid stones contribute substantially to that ascending curve and may be related to chronic the growing epidemic of obesity and diabetes mellitus.